Porter & Schon: Baxter's The Foot and Ankle in Sport, 2nd ed.

Section 5 - Athletic Shoes, Orthoses, and Rehabilitation

Chapter 27 - Orthoses and insert management of common foot and ankle problems

John S. Gould,David Ford

CHAPTER CONTENTS

Introduction

Forefoot

Midfoot

Hindfoot

Ankle

Knee pathology

Conclusions

Suggested reading

Introduction

The proper use of shoe inserts (orthotic devices/orthoses), shoe modifications, and, on occasion, braces, provides an armamentarium of nonoperative solutions to a wide range of foot problems. These approaches may be curative or palliative, permanent or temporizing, and may avoid the need for surgery or be an adjunct to it. It is essential that the pedorthist has the knowledge of materials, their durability and wear characteristics, fabrication skills, fitting capabilities, and imagination to carry out his or her part of the equation. To assist in the details of the prescription, he or she should also know enough biomechanics to understand the effect that the device or modification will have on the foot. If the physician—whether an orthopaedist, a rheumatologist, a physiatrist, or even an endocrinologist managing a diabetic—is personally to prescribe, he or she must know something about these devices or refer to someone who does. We do not feel that the pedorthist should be the prescriber any more than a pharmacist should prescribe drugs. Consequently, the physician should know what effects he or she wishes to achieve with the device and shoe modification and generally how the device should be made. He or she does not need to know about specific materials or fabrication or fitting. The ideal arrangement for patient care is for the pedorthist actually to attend the clinic with the physician so that there is a complete understanding of these issues when the patient is seen and a disposition provided. Many orthopaedic foot and ankle specialists have this arrangement and have such persons in their own foot and ankle clinics. Sports medicine specialists usually have ready access to pedorthists and always to physical therapists, who can act as an intermediary between the physician and the pedorthist. It is totally outdated for a physician to mix his or her own medications or make his or her own orthoses in the office, although this comment does not exclude the use of some over-the-counter devices that may be available in such circumstances.

In this chapter, we present information anatomically, starting with the forefoot and progressing proximally, as the physician may encounter in a patient. Problems in the athlete are highlighted. A variety of diagnoses that present in these areas are covered. It is fully accepted that there are various alternative methods to achieve the same effect. We do not attempt to be comprehensive in suggesting solutions but discuss the options we use that have proved to be effective in our practice.

Forefoot

Intractable plantar keratosis (IPK)

IPKs are calluses under bony prominences on the plantar aspect of the foot. They may be caused by a plantarflexed metatarsal head because of a hammertoe or a fracture, the elevation of an adjacent lesser toe metatarsal head that causes a transfer of pressure, or developmental problems of a similar nature (second metatarsal head callus adjacent to a bunion; a rotated fifth metatarsal head in a bunionette, a prominent sesamoid, and so forth). The solution is relatively simple: material is placed proximal to or around the prominent area (“posting”) to “offload” the prominent area and softer material is placed under the callus and prominence to cushion it. Using a material such as cork built into the insert material, we make a full-length, total-contact insert (TCI) with posting proximal to the lesion and create a well under the lesion. We then fill this well with a viscoelastic polymer, which adds excellent cushion, does not flow out of the well, and compresses more slowly than most other materials (Figs. 27-1 and 27-2 [0010] [0020]). A similar solution is used for apical calluses (on the tips of hammer, claw, or mallet toes).

Figure 27-2 Plantar surface of total-contact insert (TCI), with cork posting around the area of intractable plantar keratosis (IPK). The relief well within the posted area is filled with a viscoelastic polymer.

Morton's neuroma or intermetatarsal neuritis

Irritation of the intermetatarsal nerve, which leads to neuritis or intraneural fibrosis (the Morton's neuroma), is anatomically caused by the distal edge of the intermetatarsal ligament between the adjacent plantar plates of the metatarsophalangeal (MTP) joint. A metatarsal pad made of felt or other less compressible materials can be placed under the adjacent metatarsals proximal to the condylar heads of the adjacent metatarsals, thereby elevating them to decrease the contact of the edge of the plate when the patient is standing and walking. Some doctors place the pad on the patient's foot with some adhesive or attach it to the sock liner in the shoe. We prefer to incorporate the pad into a total-contact insert, professionally placing the pad in the right place for the patient (Figs. 27-3 and 27-4 [0030] [0040]). We also may add other features to the insert, such as longitudinal arch support when a symptomatic, flexible flatfoot accompanies the problem.

Figure 27-4 Plantar surface of total-contact insert (TCI) with metatarsal pad in place proximal to 2/3 and 3/4 interspaces.

Ulcers under the metatarsal heads

Ulcers or deep blisters may occur under the metatarsal heads. This is a particularly common and challenging condition with the insensate foot but can occur in athletes as well. Although it is critical to analyze why the ulcer or blister occurred and to recognize the presence of structural problems, the pedorthic approach is an important adjunct to care. The insert should be full length, with posting around a relief well under the ulcer. Again, we fill this well with the viscoelastic polymer. In addition, a relief well also is created in the insole of the shoe by use of a burring tool. Finally, a mild rocker sole is placed on the outside of the shoe with the apex proximal to the ulcer site ( Fig. 27-5 ). In the past, a metatarsal bar was placed in this location of the outer sole, but the rocker sole allows much easier walking than the bar. Before this stage of care, some surgeons may use total-contact casting, various commercially available boots that unweight the sole of the foot, and heel-weight-bearing–only postsurgical shoes. All of these measures may, at one stage or another, be adjunctive during the care of these problems. The orthoses and modified shoe may be used after the acute care to prevent later recurrence.

The treatment of an inflammatory condition of these joints should be immobilization while still allowing the patient to ambulate. This can be accomplished by using a stiff-sole shoe or insert. This effect can be obtained by placing a thin, spring-steel shank between the cushioned, total-contact insert and the insole on the shoe, or by incorporating the stiff material within the insert, or adding it to the sole of the shoe between the outer sole and midsole, or using a shoe that is made with a stiff shoe from the factory (Figs. 27-6 and 27-7 [0060] [0070]). It is essential, however, to also use a rocker sole on the shoe (seeFig. 27-5 ) so that the patient can walk without the foot lifting up within the shoe; this would not only make the walking difficult but also increase the symptomatology. In a patient with hallux rigidus, there are two problems: pain in the joint from impingement, arthritis, and synovitis, and lack of motion. The previous prescription deals with these problems well, but some physicians will use the more rigid insert “Morton's extension,” which lies from the heel to the end of the great toe but not all the way across the foot ( Fig. 27-8 ).

Figure 27-6 Full-length, spring-steel shank, which may be placed under a total-contact insert (TCI), incorporated within it, or placed in the sole of the shoe.

Figure 27-7 Plantar surface of a total-contact insert (TCI) with a steel shank before incorporation.

Figure 27-8 Plantar surface of a total-contact insert (TCI) with a steel-shank Morton's extension before incorporation.

In the rare athlete with rheumatoid arthritis foot, not only is there arthritis of the joints but also there may be dislocations at the MTP joints with hammertoes, plantar prominences, and nodules. Again, the stiff rocker sole is essential, but one must add the proximal posting, relief wells filled with viscoelastic material, and one additional orthotic plus two other shoe modifications. The first is increased depth of the toe box to accommodate the toe deformities. The second is softer materials for this hypersensitive foot, such as deerskin or an elastic synthetic material (e.g., Spandex). Both the elastic-material shoe and the deerskin are available over the counter and are lighter in weight than the calfskin (although perhaps less durable for scuffing and wear). We seldom prescribe custom shoes (made specifically for the individual patient) rather than these “prescription shoes,” which are more readily available, less costly, and better in appearance. Finally, we use a multi-ply insert for rheumatoid patients to provide increased cushioning.

Other joint conditions can affect the forefoot locally. Freiberg's infraction is treated as an inflammatory arthritis of the MTP joint with a stiff rocker sole and a relief well under the metatarsal head if it is tender. The turf-toe is a general term for a hyperextension injury to the plantar plate of the MTP joint of the great toe. The injury can be as simple as a minor tear of the plate, with or without intra-articular synovitis, or as complex as complete avulsion of the plate, with retraction of the sesamoids and with or without subluxation of the joint. Various articular surface injuries can occur, from a chondral abrasion to an osteochondral fracture. Severe injuries should be treated surgically, for example when retraction of the sesamoids is noted or when an injury and symptoms become chronic. The rocker sole is essential, and a stiffening device is added to the insert or sole of the shoe, as noted. For many running athletes, the rocker sole is a routine modification to their shoes, and a stiff insert or sole is compatible with their sporting function. A professional tour golfer can wear an insert but cannot modify his or her shoe. A rocker sole can be tolerated in football and lacrosse, but less so in basketball and tennis.

Sesamoid pathology

For sesamoiditis, the stiff-sole approach with a rocker is appropriate, but we also add a relief well with the viscoelastic polymer ( Fig. 27-9 ). When there is an IPK under a prominent sesamoid, the relief well alone is sufficient, with proximal or surrounding posting. For avascular necrosis and fracture care, the stiff rocker sole may be a satisfactory temporizing approach until definitive surgical measures can be taken.

Figure 27-9 Plantar surface of a total-contact insert (TCI) with a relief well filled with viscoelastic polymer under first metatarsal head and sesamoids.

Midfoot

Plantar fibromatosis

Thickening of the plantar fascia because of plantar fibromatosis, a benign but aggressive tumor, can cause pain resulting from tenderness of the lesion in its early stages or because of pressure on the underlying tissues, including the plantar nerves. Good total-contact inserts with an appropriately placed relief well filled with the viscoelastic polymer can be adequate treatment. If the lesion is particularly large, the insole also can be burred out; and finally, the sole of the shoe can be modified by use of what is called a “double rocker” sole. In this situation, the sole of the shoe becomes concave under the lesion and convex on either side of it ( Fig. 27-10 ).

Figure 27-10 Double rocker sole for midfoot plantar lesions.

Midfoot Arthritis

Tarsometatarsal (TMT), naviculocuneiform, and transverse tarsal arthritis all are treated with a stiff rocker sole shoe and total-contact inserts. The two more proximal levels and, to a slight degree, the TMT, also have some degree of varus/valgus and abduction/adduction and pronation/supination movement. This is controlled by use of an insert, which cups the heel more and is higher distally, medially, and laterally; this is the University of California Biomechanical Laboratories (UCBL) type ( Fig. 27-11 ,A and B ).

Figure 27-11 (A) Full-length University of California Biomechanical Laboratories (UCBL) insert with deep heel cup and high sides to control subtalar and transverse tarsal motion (forefoot component of the insert has not been trimmed to final contour). (B) Close-up view of deep heel cup and sides in UCBL insert.

Hindfoot

Plantar fasciitis

Plantar fasciitis, an enthesopathy of the origin of the plantar fascia on the medial tubercular process of the calcaneus, usually is a self-limited disease. Stretching exercises and a device to cushion the heel are the fundamental approaches to treatment. Over-the-counter heel cups and various heel cup and longitudinal arch supportive devices have been prescribed ( Fig. 27-12 ). The pedorthic concept is to support the plantar fascia to decrease the strain on this structure and to provide a heel cup to gather the fat pad and decrease the pressure on the sensitive point on the medial aspect of the heel. In chronic cases, we prescribe a custom-made insert, either full length or three-quarter length (with Velcro on the underside to prevent the device from slipping out of place). A shallow cup is created with posting of the longitudinal arch, thus satisfying the pedorthic concept. It also is important to flatten out the outside of the heel component so that the insert will not rock in the shoe. In the athlete, it also is important to use a “topping” on the insert that is both nonskid and washable.

Figure 27-12 Silicone heel cups.

Tarsal tunnel syndrome with or without chronic plantar fasciitis

Patients with plantar fasciitis may become chronic with attenuation of the fascia and, at times, neuritic symptoms. In these patients, the insert with its posted arch increases their pain. In these patients, we use a full-length, total-contact insert, post the arch, and add a “nerve- relief channel,” filled with the viscoelastic material. The channel starts at the medial wall of the insert under the posterior tibial nerve and its lateral plantar nerve branch over the soft spot on the medial aspect of the heel pad where the nerve enters the foot. It continues onto the plantar aspect of the heel, following the nerve course ( Fig. 27-13, A and B ). In cases of central heel-pad syndrome, which includes the first branch of the lateral plantar nerve, the channel is widened posteriorly and on the plantar pad to include this nerve area. This also is done when the patient complains of pain around the peripheral margin of the heel or on the lateral border, all symptoms of involvement of this nerve branch.

Flexible flatfoot is treated with a full-length or three-quarter–length total-contact insert, usually of the UCBL variety. The three-quarter length does not add material under the forefoot and therefore is easier to wear in a variety of shoes, including loafers ( Fig. 27-14, A and B ). When the insertion of the posterior tibial tendon is tender, particularly with a prominent accessory navicular, a relief channel with the viscoelastic filler is used. In early adolescence, when this condition is most prevalent and the foot is still growing, the inserts may need adjustment at frequent intervals, and many pedorthists will adjust their fees to make this approach more acceptable to parents. If the patient has a juvenile bunion associated, the shoewear also must be forgiving, and shoes made of flexible material and with available wider widths are needed. Because this flatfoot is flexible, it is essential that the fitting of the insert be done in a nonweight-bearing mode to properly position the foot in a neutral position of the talonavicular and naviculocuneiform joints (no sag in the talometatarsal angle or abduction or uncovering of the talus at the talonavicular joint on the anterior-posterior view) ( Fig. 27-15 ).

Figure 27-15 Plaster mold of the plantar aspect of the foot made from an impression taken of a patient's foot with a foam box or casting. The total-contact insert (TCI) is vacuum formed from the mold.

Fixed flatfoot deformity in the adolescent

Fixed flatfoot often is a condition that requires surgery for various tarsal coalitions. When an insert is indicated, it must be accommodative and must cushion the foot properly, particularly under the prominent talar head. The insert is a well-stabilized UCBL (the outer surface is flattened to prevent rocking) with a relief channel under the high contact area ( Fig. 27-16 ).

Figure 27-16 Before (L) and after (R) views of the heel portion of an insert in the fabrication process. The plantar aspect of the insert's heel component is squared off with grinding and sanding to stabilize the insert in the shoe and has the desired effect of properly supporting the foot.

Cavus or cavovarus foot

The patient with the cavus foot has numerous symptoms at various times. First, there is tripod weight bearing with high contact and often with callusing under the first and fifth metatarsal heads and the heel. The high arch causes dorsal pressure on the foot, possibly irritating the superficial peroneal nerve. Dorsal arch pain also may occur, with or without plantar fasciitis. The lack of flexibility also contributes to higher impact on the heel. Finally, the varus position of the heel places lateral stress on the ankle ligaments. A total-contact insert, which fills the arch, helps to distribute the weight bearing better, and posting behind the first and fifth metatarsal heads, with relief under them and the heel, is added. A wedge of solid ankle cushion heel (SACH) material, which has more flexibility than the usual heel leather, is added to the shoe heel, along with a lateral heel flare to decrease the tendency for the heel to roll, an action that puts stress on the ankle ( Fig. 27-17 ). A crepe sole is more flexible than leather and also is desirable, along with a rocker design, to compensate for the lack of flexibility. The middle-aged patient's now-symptomatic cavus foot can be relieved with this combination of insert and shoe modification.

Figure 27-17 A lateral heel flare has been added to the heel of this running shoe to prevent a varus roll and increased stress on the lateral ankle. The flare can be increased when heel varus is more pronounced.

Insertional tendinitis of the tendo achilles and sever's disease

Although the insertional tendinitis of the tendo Achilles occurs in middle age and Sever's disease occurs in adolescence, both are treated similarly. A lift of ⅜ to ⅝ inch is added inside or outside the shoe to decrease stress on the tendon, and the heel counter is padded with a cushioning material, or a backless shoe is used. Alternatively, there are over-the-counter devices in which a silicone pad is attached to a little sock, which can be worn with the heel lift. In addition, an over-the-counter device also has been fabricated that pads around the sensitive heel area and includes a lift under the heel ( Fig. 27-18 ).

Figure 27-18 An over-the-counter anklet to protect the tendo Achilles for insertional tendinitis. Padding is provided on either side of the tendon to help cushion the structure. A heel cup/extension or lift also is shown and is used with the anklet. Some brands also incorporate the heel lift into the lining of the anklet.

Posterior tibial tendon dysfunction

Although posterior tibial tendon dysfunction is common in middle age, tenosynovitis, stage one and early stage two of the posterior tibial tendon dysfunction syndrome occur in the younger patient. Support of the longitudinal arch is essential, along with control of the hindfoot to prevent valgus. We tend to use the UCBL insert with posting of the longitudinal arch to control this foot. The standard total-contact insert with the posted arch can be sufficient, along with various similar over-the-counter devices. In addition, it is essential to use a firm medial counter. This can be provided over the counter in many brand-name running shoes. It also can be added by various means, ranging from simple fiberglassing of the counter (which does not seem to hold up) to adding material to the outside, such as a synthetic foam material (to avoid adding significant weight to the shoe) covered by leather ( Fig. 27-19 ). When a sufficient course of a good, nonoperative regimen is not successful, surgery may be indicated.

Figure 27-19 A medial stabilizer is added to the medial counter of the shoe for posterior tibial tendinitis or posterior tibial tendon dysfunction.

Ankle

Subtalar arthritis, sinus tarsi syndrome

For subtalar arthritis, the UCBL insert can support and control the motion in the subtalar joint and is the device of choice. Sinus tarsi syndrome, apparently synovitis of the subtalar joint secondary to intra-articular ligament injury, is treated primarily by splinting with an orthotic device and prescribing medications, with arthroscopic debridement as a subsequent alternative.

Peroneal subluxation, peroneal tenosynovitis, peroneal tears

Orthotic treatment of peroneal subluxation, peroneal tenosynovitis, and peroneal tears constitutes, in our opinion, a minor adjunct to what often are surgical conditions. In synovitis, in particular, a lateral heel wedge with an insert to create a valgus heel position to help splint these tendons may be used.

Ankle ligament sprains

Taping, bandaging, and over-the-counter ankle supports constitute part of the treatment of ankle ligament sprains. We may use elastic sheath supports, which provide medial/lateral support and compression, or lace-up devices with Velcro-strap support in the early stages of management, along with physical therapy. Many athletes who wear cleated shoes have their ankles taped for practice and games. Few tolerate braces for prophylaxis of sprains.

Knee Pathology

Some sports medicine and knee specialists will prescribe orthotic devices with medial or lateral heel wedges to load or unload the medial or lateral knee compartments, and after sprains, strains, and suspected menisci injuries. Such wedges also may be helpful in early unicompartmental arthritis.

Conclusions

Orthotic devices and modification of standard and prescription shoes are an essential part of the armamentarium of the orthopaedic surgeon specializing in foot and ankle and sports medicine. Some over-the-counter devices are appropriate, and, in other instances, custom devices should be fabricated. Many of these approaches may return an athlete to participation rapidly. When surgery is indicated, the devices may also be a valuable adjunct to care.